Merge pull request #19688 from ChayimFriedman2/less-unused

internal: More `shrink_to_fit()` and upgrade dashmap and hashbrown

Cargo.lock

@@ -79,7 +79,7 @@ name = "base-db"
 version = "0.0.0"
 dependencies = [
  "cfg",
- "dashmap 5.5.3",
+ "dashmap",
  "intern",
  "la-arena 0.3.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "query-group-macro",
@@ -323,19 +323,6 @@ dependencies = [
  "windows-sys 0.59.0",
 ]
 
-[[package]]
-name = "dashmap"
-version = "5.5.3"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "978747c1d849a7d2ee5e8adc0159961c48fb7e5db2f06af6723b80123bb53856"
-dependencies = [
- "cfg-if",
- "hashbrown 0.14.5",
- "lock_api",
- "once_cell",
- "parking_lot_core",
-]
-
 [[package]]
 name = "dashmap"
 version = "6.1.0"
@@ -1051,7 +1038,7 @@ dependencies = [
 name = "intern"
 version = "0.0.0"
 dependencies = [
- "dashmap 5.5.3",
+ "dashmap",
  "hashbrown 0.14.5",
  "rustc-hash 2.1.1",
  "triomphe",
@@ -2045,7 +2032,7 @@ checksum = "1be22155f8d9732518b2db2bf379fe6f0b2375e76b08b7c8fe6c1b887d548c24"
 dependencies = [
  "boxcar",
  "crossbeam-queue",
- "dashmap 6.1.0",
+ "dashmap",
  "hashbrown 0.15.2",
  "hashlink",
  "indexmap",

Cargo.toml

@@ -158,11 +158,10 @@ triomphe = { version = "0.1.14", default-features = false, features = ["std"] }
 url = "2.5.4"
 xshell = "0.2.7"
 
-
 # We need to freeze the version of the crate, as the raw-api feature is considered unstable
-dashmap = { version = "=5.5.3", features = ["raw-api"] }
+dashmap = { version = "=6.1.0", features = ["raw-api", "inline"] }
 # We need to freeze the version of the crate, as it needs to match with dashmap
-hashbrown = { version = "=0.14.5", features = [
+hashbrown = { version = "0.14.0", features = [
   "inline-more",
 ], default-features = false }
 

crates/base-db/src/input.rs

@@ -422,8 +422,8 @@ impl CrateGraphBuilder {
         edition: Edition,
         display_name: Option<CrateDisplayName>,
         version: Option<String>,
-        cfg_options: CfgOptions,
+        mut cfg_options: CfgOptions,
-        potential_cfg_options: Option<CfgOptions>,
+        mut potential_cfg_options: Option<CfgOptions>,
         mut env: Env,
         origin: CrateOrigin,
         is_proc_macro: bool,
@@ -431,6 +431,10 @@ impl CrateGraphBuilder {
         ws_data: Arc<CrateWorkspaceData>,
     ) -> CrateBuilderId {
         env.entries.shrink_to_fit();
+        cfg_options.shrink_to_fit();
+        if let Some(potential_cfg_options) = &mut potential_cfg_options {
+            potential_cfg_options.shrink_to_fit();
+        }
         self.arena.alloc(CrateBuilder {
             basic: CrateData {
                 root_file_id,

crates/cfg/src/lib.rs

@@ -110,6 +110,11 @@ impl CfgOptions {
         enabled.sort_unstable();
         HashableCfgOptions { _enabled: enabled }
     }
+
+    #[inline]
+    pub fn shrink_to_fit(&mut self) {
+        self.enabled.shrink_to_fit();
+    }
 }
 
 impl Extend<CfgAtom> for CfgOptions {

crates/hir-def/src/item_tree.rs

@@ -223,7 +223,10 @@ impl ItemTree {
     }
 
     fn shrink_to_fit(&mut self) {
-        if let Some(data) = &mut self.data {
+        let ItemTree { top_level, attrs, data } = self;
+        top_level.shrink_to_fit();
+        attrs.shrink_to_fit();
+        if let Some(data) = data {
             let ItemTreeData {
                 uses,
                 extern_crates,

crates/hir-ty/src/infer.rs

@@ -493,7 +493,7 @@ pub struct InferenceResult {
     /// ```
     /// the first `rest` has implicit `ref` binding mode, but the second `rest` binding mode is `move`.
     pub binding_modes: ArenaMap<PatId, BindingMode>,
-    pub expr_adjustments: FxHashMap<ExprId, Vec<Adjustment>>,
+    pub expr_adjustments: FxHashMap<ExprId, Box<[Adjustment]>>,
     pub(crate) closure_info: FxHashMap<ClosureId, (Vec<CapturedItem>, FnTrait)>,
     // FIXME: remove this field
     pub mutated_bindings_in_closure: FxHashSet<BindingId>,
@@ -785,8 +785,8 @@ impl<'a> InferenceContext<'a> {
         // Comment from rustc:
         // Even though coercion casts provide type hints, we check casts after fallback for
         // backwards compatibility. This makes fallback a stronger type hint than a cast coercion.
-        let mut apply_adjustments = |expr, adj| {
+        let mut apply_adjustments = |expr, adj: Vec<_>| {
-            expr_adjustments.insert(expr, adj);
+            expr_adjustments.insert(expr, adj.into_boxed_slice());
         };
         let mut set_coercion_cast = |expr| {
             coercion_casts.insert(expr);
@@ -808,22 +808,27 @@ impl<'a> InferenceContext<'a> {
             *ty = table.resolve_completely(ty.clone());
             *has_errors = *has_errors || ty.contains_unknown();
         }
+        type_of_expr.shrink_to_fit();
         for ty in type_of_pat.values_mut() {
             *ty = table.resolve_completely(ty.clone());
             *has_errors = *has_errors || ty.contains_unknown();
         }
+        type_of_pat.shrink_to_fit();
         for ty in type_of_binding.values_mut() {
             *ty = table.resolve_completely(ty.clone());
             *has_errors = *has_errors || ty.contains_unknown();
         }
+        type_of_binding.shrink_to_fit();
         for ty in type_of_rpit.values_mut() {
             *ty = table.resolve_completely(ty.clone());
             *has_errors = *has_errors || ty.contains_unknown();
         }
+        type_of_rpit.shrink_to_fit();
         for ty in type_of_for_iterator.values_mut() {
             *ty = table.resolve_completely(ty.clone());
             *has_errors = *has_errors || ty.contains_unknown();
         }
+        type_of_for_iterator.shrink_to_fit();
 
         *has_errors |= !type_mismatches.is_empty();
 
@@ -838,6 +843,7 @@ impl<'a> InferenceContext<'a> {
             )
             .is_ok()
         });
+        type_mismatches.shrink_to_fit();
         diagnostics.retain_mut(|diagnostic| {
             use InferenceDiagnostic::*;
             match diagnostic {
@@ -866,24 +872,29 @@ impl<'a> InferenceContext<'a> {
             }
             true
         });
+        diagnostics.shrink_to_fit();
         for (_, subst) in method_resolutions.values_mut() {
             *subst = table.resolve_completely(subst.clone());
             *has_errors =
                 *has_errors || subst.type_parameters(Interner).any(|ty| ty.contains_unknown());
         }
+        method_resolutions.shrink_to_fit();
         for (_, subst) in assoc_resolutions.values_mut() {
             *subst = table.resolve_completely(subst.clone());
             *has_errors =
                 *has_errors || subst.type_parameters(Interner).any(|ty| ty.contains_unknown());
         }
+        assoc_resolutions.shrink_to_fit();
         for adjustment in expr_adjustments.values_mut().flatten() {
             adjustment.target = table.resolve_completely(adjustment.target.clone());
             *has_errors = *has_errors || adjustment.target.contains_unknown();
         }
+        expr_adjustments.shrink_to_fit();
         for adjustment in pat_adjustments.values_mut().flatten() {
             *adjustment = table.resolve_completely(adjustment.clone());
             *has_errors = *has_errors || adjustment.contains_unknown();
         }
+        pat_adjustments.shrink_to_fit();
         result.tuple_field_access_types = tuple_field_accesses_rev
             .into_iter()
             .enumerate()
@@ -893,6 +904,7 @@ impl<'a> InferenceContext<'a> {
                     *has_errors || subst.type_parameters(Interner).any(|ty| ty.contains_unknown());
             })
             .collect();
+        result.tuple_field_access_types.shrink_to_fit();
 
         result.diagnostics = diagnostics;
 
@@ -1261,7 +1273,7 @@ impl<'a> InferenceContext<'a> {
         self.result.type_of_expr.insert(expr, ty);
     }
 
-    fn write_expr_adj(&mut self, expr: ExprId, adjustments: Vec<Adjustment>) {
+    fn write_expr_adj(&mut self, expr: ExprId, adjustments: Box<[Adjustment]>) {
         if adjustments.is_empty() {
             return;
         }

crates/hir-ty/src/infer/closure.rs

@@ -869,8 +869,8 @@ impl CapturedItemWithoutTy {
 impl InferenceContext<'_> {
     fn place_of_expr(&mut self, tgt_expr: ExprId) -> Option<HirPlace> {
         let r = self.place_of_expr_without_adjust(tgt_expr)?;
-        let default = vec![];
+        let adjustments =
-        let adjustments = self.result.expr_adjustments.get(&tgt_expr).unwrap_or(&default);
+            self.result.expr_adjustments.get(&tgt_expr).map(|it| &**it).unwrap_or_default();
         apply_adjusts_to_place(&mut self.current_capture_span_stack, r, adjustments)
     }
 
@@ -1701,7 +1701,7 @@ impl InferenceContext<'_> {
             for (derefed_callee, callee_ty, params, expr) in exprs {
                 if let &Expr::Call { callee, .. } = &self.body[expr] {
                     let mut adjustments =
-                        self.result.expr_adjustments.remove(&callee).unwrap_or_default();
+                        self.result.expr_adjustments.remove(&callee).unwrap_or_default().into_vec();
                     self.write_fn_trait_method_resolution(
                         kind,
                         &derefed_callee,
@@ -1710,7 +1710,7 @@ impl InferenceContext<'_> {
                         &params,
                         expr,
                     );
-                    self.result.expr_adjustments.insert(callee, adjustments);
+                    self.result.expr_adjustments.insert(callee, adjustments.into_boxed_slice());
                 }
             }
         }

crates/hir-ty/src/infer/coerce.rs

@@ -148,11 +148,11 @@ impl CoerceMany {
             if let (Ok(result1), Ok(result2)) = (result1, result2) {
                 ctx.table.register_infer_ok(InferOk { value: (), goals: result1.goals });
                 for &e in &self.expressions {
-                    ctx.write_expr_adj(e, result1.value.0.clone());
+                    ctx.write_expr_adj(e, result1.value.0.clone().into_boxed_slice());
                 }
                 ctx.table.register_infer_ok(InferOk { value: (), goals: result2.goals });
                 if let Some(expr) = expr {
-                    ctx.write_expr_adj(expr, result2.value.0);
+                    ctx.write_expr_adj(expr, result2.value.0.into_boxed_slice());
                     self.expressions.push(expr);
                 }
                 return self.final_ty = Some(target_ty);
@@ -182,7 +182,7 @@ impl CoerceMany {
         {
             self.final_ty = Some(res);
             for &e in &self.expressions {
-                ctx.write_expr_adj(e, adjustments.clone());
+                ctx.write_expr_adj(e, adjustments.clone().into_boxed_slice());
             }
         } else {
             match cause {
@@ -263,7 +263,7 @@ impl InferenceContext<'_> {
     ) -> Result<Ty, TypeError> {
         let (adjustments, ty) = self.coerce_inner(from_ty, to_ty, coerce_never)?;
         if let Some(expr) = expr {
-            self.write_expr_adj(expr, adjustments);
+            self.write_expr_adj(expr, adjustments.into_boxed_slice());
         }
         Ok(ty)
     }

crates/hir-ty/src/infer/expr.rs

@@ -812,7 +812,7 @@ impl InferenceContext<'_> {
                         self_ty.clone(),
                         self.table.new_lifetime_var(),
                     ));
-                    self.write_expr_adj(*base, adj);
+                    self.write_expr_adj(*base, adj.into_boxed_slice());
                     if let Some(func) = self
                         .db
                         .trait_items(index_trait)
@@ -1356,10 +1356,10 @@ impl InferenceContext<'_> {
                     if let TyKind::Ref(mtbl, lt, _) = p_left.kind(Interner) {
                         self.write_expr_adj(
                             lhs,
-                            vec![Adjustment {
+                            Box::new([Adjustment {
                                 kind: Adjust::Borrow(AutoBorrow::Ref(lt.clone(), *mtbl)),
                                 target: p_left.clone(),
-                            }],
+                            }]),
                         );
                     }
                 }
@@ -1368,10 +1368,10 @@ impl InferenceContext<'_> {
                     if let TyKind::Ref(mtbl, lt, _) = p_right.kind(Interner) {
                         self.write_expr_adj(
                             rhs,
-                            vec![Adjustment {
+                            Box::new([Adjustment {
                                 kind: Adjust::Borrow(AutoBorrow::Ref(lt.clone(), *mtbl)),
                                 target: p_right.clone(),
-                            }],
+                            }]),
                         );
                     }
                 }
@@ -1627,7 +1627,7 @@ impl InferenceContext<'_> {
 
         match self.lookup_field(&receiver_ty, name) {
             Some((ty, field_id, adjustments, is_public)) => {
-                self.write_expr_adj(receiver, adjustments);
+                self.write_expr_adj(receiver, adjustments.into_boxed_slice());
                 self.result.field_resolutions.insert(tgt_expr, field_id);
                 if !is_public {
                     if let Either::Left(field) = field_id {
@@ -1662,7 +1662,7 @@ impl InferenceContext<'_> {
                     Some((adjust, func, _)) => {
                         let (ty, adjustments) = adjust.apply(&mut self.table, receiver_ty);
                         let substs = self.substs_for_method_call(tgt_expr, func.into(), None);
-                        self.write_expr_adj(receiver, adjustments);
+                        self.write_expr_adj(receiver, adjustments.into_boxed_slice());
                         self.write_method_resolution(tgt_expr, func, substs.clone());
 
                         self.check_method_call(
@@ -1725,7 +1725,7 @@ impl InferenceContext<'_> {
                         tgt_expr,
                     );
                 }
-                self.write_expr_adj(callee, adjustments);
+                self.write_expr_adj(callee, adjustments.into_boxed_slice());
                 (params, ret_ty)
             }
             None => {
@@ -1809,7 +1809,7 @@ impl InferenceContext<'_> {
                 }
 
                 let (ty, adjustments) = adjust.apply(&mut self.table, receiver_ty);
-                self.write_expr_adj(receiver, adjustments);
+                self.write_expr_adj(receiver, adjustments.into_boxed_slice());
 
                 let substs = self.substs_for_method_call(tgt_expr, func.into(), generic_args);
                 self.write_method_resolution(tgt_expr, func, substs.clone());
@@ -1828,7 +1828,7 @@ impl InferenceContext<'_> {
                 let field_with_same_name_exists = match self.lookup_field(&receiver_ty, method_name)
                 {
                     Some((ty, field_id, adjustments, _public)) => {
-                        self.write_expr_adj(receiver, adjustments);
+                        self.write_expr_adj(receiver, adjustments.into_boxed_slice());
                         self.result.field_resolutions.insert(tgt_expr, field_id);
                         Some(ty)
                     }

crates/hir-ty/src/interner.rs

@@ -43,7 +43,7 @@ impl_internable!(
     InternedWrapper<ConstData>,
     InternedWrapper<ConstScalar>,
     InternedWrapper<Vec<CanonicalVarKind>>,
-    InternedWrapper<Vec<ProgramClause>>,
+    InternedWrapper<Box<[ProgramClause]>>,
     InternedWrapper<Vec<QuantifiedWhereClause>>,
     InternedWrapper<SmallVec<[Variance; 16]>>,
 );
@@ -60,7 +60,7 @@ impl chalk_ir::interner::Interner for Interner {
     type InternedGoal = Arc<GoalData>;
     type InternedGoals = Vec<Goal>;
     type InternedSubstitution = Interned<InternedWrapper<SmallVec<[GenericArg; 2]>>>;
-    type InternedProgramClauses = Interned<InternedWrapper<Vec<ProgramClause>>>;
+    type InternedProgramClauses = Interned<InternedWrapper<Box<[ProgramClause]>>>;
     type InternedProgramClause = ProgramClauseData;
     type InternedQuantifiedWhereClauses = Interned<InternedWrapper<Vec<QuantifiedWhereClause>>>;
     type InternedVariableKinds = Interned<InternedWrapper<Vec<VariableKind>>>;

crates/intern/src/lib.rs

@@ -3,22 +3,20 @@
 //! Eventually this should probably be replaced with salsa-based interning.
 
 use std::{
+    borrow::Borrow,
     fmt::{self, Debug, Display},
-    hash::{BuildHasherDefault, Hash, Hasher},
+    hash::{BuildHasher, BuildHasherDefault, Hash, Hasher},
     ops::Deref,
     sync::OnceLock,
 };
 
 use dashmap::{DashMap, SharedValue};
-use hashbrown::{HashMap, hash_map::RawEntryMut};
+use hashbrown::raw::RawTable;
 use rustc_hash::FxHasher;
 use triomphe::Arc;
 
 type InternMap<T> = DashMap<Arc<T>, (), BuildHasherDefault<FxHasher>>;
-type Guard<T> = dashmap::RwLockWriteGuard<
+type Guard<T> = dashmap::RwLockWriteGuard<'static, RawTable<(Arc<T>, SharedValue<()>)>>;
-    'static,
-    HashMap<Arc<T>, SharedValue<()>, BuildHasherDefault<FxHasher>>,
->;
 
 mod symbol;
 pub use self::symbol::{Symbol, symbols as sym};
@@ -28,54 +26,61 @@ pub struct Interned<T: Internable + ?Sized> {
 }
 
 impl<T: Internable> Interned<T> {
+    #[inline]
     pub fn new(obj: T) -> Self {
-        let (mut shard, hash) = Self::select(&obj);
+        Self::new_generic(obj)
-        // Atomically,
-        // - check if `obj` is already in the map
-        //   - if so, clone its `Arc` and return it
-        //   - if not, box it up, insert it, and return a clone
-        // This needs to be atomic (locking the shard) to avoid races with other thread, which could
-        // insert the same object between us looking it up and inserting it.
-        match shard.raw_entry_mut().from_key_hashed_nocheck(hash, &obj) {
-            RawEntryMut::Occupied(occ) => Self { arc: occ.key().clone() },
-            RawEntryMut::Vacant(vac) => Self {
-                arc: vac.insert_hashed_nocheck(hash, Arc::new(obj), SharedValue::new(())).0.clone(),
-            },
-        }
     }
 }
 
 impl Interned<str> {
+    #[inline]
     pub fn new_str(s: &str) -> Self {
-        let (mut shard, hash) = Self::select(s);
+        Self::new_generic(s)
-        // Atomically,
-        // - check if `obj` is already in the map
-        //   - if so, clone its `Arc` and return it
-        //   - if not, box it up, insert it, and return a clone
-        // This needs to be atomic (locking the shard) to avoid races with other thread, which could
-        // insert the same object between us looking it up and inserting it.
-        match shard.raw_entry_mut().from_key_hashed_nocheck(hash, s) {
-            RawEntryMut::Occupied(occ) => Self { arc: occ.key().clone() },
-            RawEntryMut::Vacant(vac) => Self {
-                arc: vac.insert_hashed_nocheck(hash, Arc::from(s), SharedValue::new(())).0.clone(),
-            },
-        }
     }
 }
 
 impl<T: Internable + ?Sized> Interned<T> {
     #[inline]
-    fn select(obj: &T) -> (Guard<T>, u64) {
+    pub fn new_generic<U>(obj: U) -> Self
+    where
+        U: Borrow<T>,
+        Arc<T>: From<U>,
+    {
         let storage = T::storage().get();
-        let hash = {
+        let (mut shard, hash) = Self::select(storage, obj.borrow());
-            let mut hasher = std::hash::BuildHasher::build_hasher(storage.hasher());
+        // Atomically,
-            obj.hash(&mut hasher);
+        // - check if `obj` is already in the map
-            hasher.finish()
+        //   - if so, clone its `Arc` and return it
+        //   - if not, box it up, insert it, and return a clone
+        // This needs to be atomic (locking the shard) to avoid races with other thread, which could
+        // insert the same object between us looking it up and inserting it.
+        let bucket = match shard.find_or_find_insert_slot(
+            hash,
+            |(other, _)| **other == *obj.borrow(),
+            |(x, _)| Self::hash(storage, x),
+        ) {
+            Ok(bucket) => bucket,
+            // SAFETY: The slot came from `find_or_find_insert_slot()`, and the table wasn't modified since then.
+            Err(insert_slot) => unsafe {
+                shard.insert_in_slot(hash, insert_slot, (Arc::from(obj), SharedValue::new(())))
+            },
         };
+        // SAFETY: We just retrieved/inserted this bucket.
+        unsafe { Self { arc: bucket.as_ref().0.clone() } }
+    }
+
+    #[inline]
+    fn select(storage: &'static InternMap<T>, obj: &T) -> (Guard<T>, u64) {
+        let hash = Self::hash(storage, obj);
         let shard_idx = storage.determine_shard(hash as usize);
         let shard = &storage.shards()[shard_idx];
         (shard.write(), hash)
     }
+
+    #[inline]
+    fn hash(storage: &'static InternMap<T>, obj: &T) -> u64 {
+        storage.hasher().hash_one(obj)
+    }
 }
 
 impl<T: Internable + ?Sized> Drop for Interned<T> {
@@ -93,21 +98,20 @@ impl<T: Internable + ?Sized> Drop for Interned<T> {
 impl<T: Internable + ?Sized> Interned<T> {
     #[cold]
     fn drop_slow(&mut self) {
-        let (mut shard, hash) = Self::select(&self.arc);
+        let storage = T::storage().get();
+        let (mut shard, hash) = Self::select(storage, &self.arc);
 
         if Arc::count(&self.arc) != 2 {
             // Another thread has interned another copy
             return;
         }
 
-        match shard.raw_entry_mut().from_key_hashed_nocheck(hash, &self.arc) {
+        shard.remove_entry(hash, |(other, _)| **other == *self.arc);
-            RawEntryMut::Occupied(occ) => occ.remove(),
-            RawEntryMut::Vacant(_) => unreachable!(),
-        };
 
         // Shrink the backing storage if the shard is less than 50% occupied.
         if shard.len() * 2 < shard.capacity() {
-            shard.shrink_to_fit();
+            let len = shard.len();
+            shard.shrink_to(len, |(x, _)| Self::hash(storage, x));
         }
     }
 }

crates/intern/src/symbol.rs

@@ -2,16 +2,15 @@
 //! supporting compile time declaration of symbols that will never be freed.
 
 use std::{
-    borrow::Borrow,
     fmt,
-    hash::{BuildHasherDefault, Hash, Hasher},
+    hash::{BuildHasher, BuildHasherDefault, Hash},
     mem::{self, ManuallyDrop},
     ptr::NonNull,
     sync::OnceLock,
 };
 
 use dashmap::{DashMap, SharedValue};
-use hashbrown::{HashMap, hash_map::RawEntryMut};
+use hashbrown::raw::RawTable;
 use rustc_hash::FxHasher;
 use triomphe::Arc;
 
@@ -127,31 +126,39 @@ impl fmt::Debug for Symbol {
 const _: () = assert!(size_of::<Symbol>() == size_of::<NonNull<()>>());
 const _: () = assert!(align_of::<Symbol>() == align_of::<NonNull<()>>());
 
-static MAP: OnceLock<DashMap<SymbolProxy, (), BuildHasherDefault<FxHasher>>> = OnceLock::new();
+type Map = DashMap<Symbol, (), BuildHasherDefault<FxHasher>>;
+static MAP: OnceLock<Map> = OnceLock::new();
 
 impl Symbol {
     pub fn intern(s: &str) -> Self {
-        let (mut shard, hash) = Self::select_shard(s);
+        let storage = MAP.get_or_init(symbols::prefill);
+        let (mut shard, hash) = Self::select_shard(storage, s);
         // Atomically,
         // - check if `obj` is already in the map
         //   - if so, copy out its entry, conditionally bumping the backing Arc and return it
         //   - if not, put it into a box and then into an Arc, insert it, bump the ref-count and return the copy
         // This needs to be atomic (locking the shard) to avoid races with other thread, which could
         // insert the same object between us looking it up and inserting it.
-        match shard.raw_entry_mut().from_key_hashed_nocheck(hash, s) {
+        let bucket = match shard.find_or_find_insert_slot(
-            RawEntryMut::Occupied(occ) => Self { repr: increase_arc_refcount(occ.key().0) },
+            hash,
-            RawEntryMut::Vacant(vac) => Self {
+            |(other, _)| other.as_str() == s,
-                repr: increase_arc_refcount(
+            |(x, _)| Self::hash(storage, x.as_str()),
-                    vac.insert_hashed_nocheck(
+        ) {
-                        hash,
+            Ok(bucket) => bucket,
-                        SymbolProxy(TaggedArcPtr::arc(Arc::new(Box::<str>::from(s)))),
+            // SAFETY: The slot came from `find_or_find_insert_slot()`, and the table wasn't modified since then.
+            Err(insert_slot) => unsafe {
+                shard.insert_in_slot(
+                    hash,
+                    insert_slot,
+                    (
+                        Symbol { repr: TaggedArcPtr::arc(Arc::new(Box::<str>::from(s))) },
                         SharedValue::new(()),
-                    )
+                    ),
-                    .0
+                )
-                    .0,
-                ),
             },
-        }
+        };
+        // SAFETY: We just retrieved/inserted this bucket.
+        unsafe { bucket.as_ref().0.clone() }
     }
 
     pub fn integer(i: usize) -> Self {
@@ -180,38 +187,34 @@ impl Symbol {
         symbols::__empty.clone()
     }
 
+    #[inline]
     pub fn as_str(&self) -> &str {
         self.repr.as_str()
     }
 
     #[inline]
     fn select_shard(
+        storage: &'static Map,
         s: &str,
-    ) -> (
+    ) -> (dashmap::RwLockWriteGuard<'static, RawTable<(Symbol, SharedValue<()>)>>, u64) {
-        dashmap::RwLockWriteGuard<
+        let hash = Self::hash(storage, s);
-            'static,
-            HashMap<SymbolProxy, SharedValue<()>, BuildHasherDefault<FxHasher>>,
-        >,
-        u64,
-    ) {
-        let storage = MAP.get_or_init(symbols::prefill);
-        let hash = {
-            let mut hasher = std::hash::BuildHasher::build_hasher(storage.hasher());
-            s.hash(&mut hasher);
-            hasher.finish()
-        };
         let shard_idx = storage.determine_shard(hash as usize);
         let shard = &storage.shards()[shard_idx];
         (shard.write(), hash)
     }
 
+    #[inline]
+    fn hash(storage: &'static Map, s: &str) -> u64 {
+        storage.hasher().hash_one(s)
+    }
+
     #[cold]
     fn drop_slow(arc: &Arc<Box<str>>) {
-        let (mut shard, hash) = Self::select_shard(arc);
+        let storage = MAP.get_or_init(symbols::prefill);
+        let (mut shard, hash) = Self::select_shard(storage, arc);
 
         match Arc::count(arc) {
-            0 => unreachable!(),
+            0 | 1 => unreachable!(),
-            1 => unreachable!(),
             2 => (),
             _ => {
                 // Another thread has interned another copy
@@ -219,19 +222,17 @@ impl Symbol {
             }
         }
 
-        let ptr = match shard.raw_entry_mut().from_key_hashed_nocheck::<str>(hash, arc.as_ref()) {
+        let s = &***arc;
-            RawEntryMut::Occupied(occ) => occ.remove_entry(),
+        let (ptr, _) = shard.remove_entry(hash, |(x, _)| x.as_str() == s).unwrap();
-            RawEntryMut::Vacant(_) => unreachable!(),
+        let ptr = ManuallyDrop::new(ptr);
-        }
-        .0
-        .0;
         // SAFETY: We're dropping, we have ownership.
-        ManuallyDrop::into_inner(unsafe { ptr.try_as_arc_owned().unwrap() });
+        ManuallyDrop::into_inner(unsafe { ptr.repr.try_as_arc_owned().unwrap() });
         debug_assert_eq!(Arc::count(arc), 1);
 
         // Shrink the backing storage if the shard is less than 50% occupied.
         if shard.len() * 2 < shard.capacity() {
-            shard.shrink_to_fit();
+            let len = shard.len();
+            shard.shrink_to(len, |(x, _)| Self::hash(storage, x.as_str()));
         }
     }
 }
@@ -276,22 +277,6 @@ impl fmt::Display for Symbol {
     }
 }
 
-// only exists so we can use `from_key_hashed_nocheck` with a &str
-#[derive(Debug, PartialEq, Eq)]
-struct SymbolProxy(TaggedArcPtr);
-
-impl Hash for SymbolProxy {
-    fn hash<H: Hasher>(&self, state: &mut H) {
-        self.0.as_str().hash(state);
-    }
-}
-
-impl Borrow<str> for SymbolProxy {
-    fn borrow(&self) -> &str {
-        self.0.as_str()
-    }
-}
-
 #[cfg(test)]
 mod tests {
     use super::*;

crates/intern/src/symbol/symbols.rs

@@ -1,15 +1,12 @@
 //! Module defining all known symbols required by the rest of rust-analyzer.
 #![allow(non_upper_case_globals)]
 
-use std::hash::{BuildHasherDefault, Hash as _, Hasher as _};
+use std::hash::{BuildHasher, BuildHasherDefault};
 
 use dashmap::{DashMap, SharedValue};
 use rustc_hash::FxHasher;
 
-use crate::{
+use crate::{Symbol, symbol::TaggedArcPtr};
-    Symbol,
-    symbol::{SymbolProxy, TaggedArcPtr},
-};
 
 macro_rules! define_symbols {
     (@WITH_NAME: $($alias:ident = $value:literal,)* @PLAIN: $($name:ident,)*) => {
@@ -28,28 +25,23 @@ macro_rules! define_symbols {
         )*
 
 
-        pub(super) fn prefill() -> DashMap<SymbolProxy, (), BuildHasherDefault<FxHasher>> {
+        pub(super) fn prefill() -> DashMap<Symbol, (), BuildHasherDefault<FxHasher>> {
-            let mut dashmap_ = <DashMap<SymbolProxy, (), BuildHasherDefault<FxHasher>>>::with_hasher(BuildHasherDefault::default());
+            let mut dashmap_ = <DashMap<Symbol, (), BuildHasherDefault<FxHasher>>>::with_hasher(BuildHasherDefault::default());
 
-            let hash_thing_ = |hasher_: &BuildHasherDefault<FxHasher>, it_: &SymbolProxy| {
+            let hasher_ = dashmap_.hasher().clone();
-                let mut hasher_ = std::hash::BuildHasher::build_hasher(hasher_);
+            let hash_one = |it_: &str| hasher_.hash_one(it_);
-                it_.hash(&mut hasher_);
-                hasher_.finish()
-            };
             {
                 $(
-
+                    let s = stringify!($name);
-                    let proxy_ = SymbolProxy($name.repr);
+                    let hash_ = hash_one(s);
-                    let hash_ = hash_thing_(dashmap_.hasher(), &proxy_);
                     let shard_idx_ = dashmap_.determine_shard(hash_ as usize);
-                    dashmap_.shards_mut()[shard_idx_].get_mut().raw_entry_mut().from_hash(hash_, |k| k == &proxy_).insert(proxy_, SharedValue::new(()));
+                    dashmap_.shards_mut()[shard_idx_].get_mut().insert(hash_, ($name, SharedValue::new(())), |(x, _)| hash_one(x.as_str()));
                 )*
                 $(
-
+                    let s = $value;
-                    let proxy_ = SymbolProxy($alias.repr);
+                    let hash_ = hash_one(s);
-                    let hash_ = hash_thing_(dashmap_.hasher(), &proxy_);
                     let shard_idx_ = dashmap_.determine_shard(hash_ as usize);
-                    dashmap_.shards_mut()[shard_idx_].get_mut().raw_entry_mut().from_hash(hash_, |k| k == &proxy_).insert(proxy_, SharedValue::new(()));
+                    dashmap_.shards_mut()[shard_idx_].get_mut().insert(hash_, ($alias, SharedValue::new(())), |(x, _)| hash_one(x.as_str()));
                 )*
             }
             dashmap_

crates/span/src/ast_id.rs

@@ -132,7 +132,7 @@ pub struct AstIdMap {
     /// Maps stable id to unstable ptr.
     arena: Arena<SyntaxNodePtr>,
     /// Reverse: map ptr to id.
-    map: hashbrown::HashMap<Idx<SyntaxNodePtr>, (), ()>,
+    map: hashbrown::HashTable<Idx<SyntaxNodePtr>>,
 }
 
 impl fmt::Debug for AstIdMap {
@@ -169,13 +169,13 @@ impl AstIdMap {
                 TreeOrder::DepthFirst
             }
         });
-        res.map = hashbrown::HashMap::with_capacity_and_hasher(res.arena.len(), ());
+        res.map = hashbrown::HashTable::with_capacity(res.arena.len());
         for (idx, ptr) in res.arena.iter() {
             let hash = hash_ptr(ptr);
-            match res.map.raw_entry_mut().from_hash(hash, |idx2| *idx2 == idx) {
+            match res.map.entry(hash, |&idx2| idx2 == idx, |&idx| hash_ptr(&res.arena[idx])) {
-                hashbrown::hash_map::RawEntryMut::Occupied(_) => unreachable!(),
+                hashbrown::hash_table::Entry::Occupied(_) => unreachable!(),
-                hashbrown::hash_map::RawEntryMut::Vacant(entry) => {
+                hashbrown::hash_table::Entry::Vacant(entry) => {
-                    entry.insert_with_hasher(hash, idx, (), |&idx| hash_ptr(&res.arena[idx]));
+                    entry.insert(idx);
                 }
             }
         }
@@ -196,8 +196,8 @@ impl AstIdMap {
     pub fn ast_id_for_ptr<N: AstIdNode>(&self, ptr: AstPtr<N>) -> FileAstId<N> {
         let ptr = ptr.syntax_node_ptr();
         let hash = hash_ptr(&ptr);
-        match self.map.raw_entry().from_hash(hash, |&idx| self.arena[idx] == ptr) {
+        match self.map.find(hash, |&idx| self.arena[idx] == ptr) {
-            Some((&raw, &())) => FileAstId {
+            Some(&raw) => FileAstId {
                 raw: ErasedFileAstId(raw.into_raw().into_u32()),
                 covariant: PhantomData,
             },
@@ -221,8 +221,8 @@ impl AstIdMap {
     fn erased_ast_id(&self, item: &SyntaxNode) -> ErasedFileAstId {
         let ptr = SyntaxNodePtr::new(item);
         let hash = hash_ptr(&ptr);
-        match self.map.raw_entry().from_hash(hash, |&idx| self.arena[idx] == ptr) {
+        match self.map.find(hash, |&idx| self.arena[idx] == ptr) {
-            Some((&idx, &())) => ErasedFileAstId(idx.into_raw().into_u32()),
+            Some(&idx) => ErasedFileAstId(idx.into_raw().into_u32()),
             None => panic!(
                 "Can't find {:?} in AstIdMap:\n{:?}\n source text: {}",
                 item,